This specification describes a vehicle engine sound enhancement system. Engine sound enhancement systems provide enhanced sound to modify the sonic and/or vibratory experience of a vehicle driver or a vehicle occupant. In a hybrid vehicle, the sound enhancement system may provide to the driver a constant sonic experience, despite changes from internal combustion power to electric motor power and to smooth the transition of the engine sound during changes. An engine sound enhancement system may allow the occupants to experience the engine sound at a loud, stimulating, level, without being annoyingly loud to persons outside the vehicle.
For further background, reference is made to U.S. patent application Ser. No. 12/716,887.